Australian-listed clean technology companies are not popular among investors who are concerned about the sector's speculative nature. There are 70 such companies listed on the Australian stock exchange, most of them very small. Investors are advised to consider investing in the following stocks which are particularly promising: Sims Group, Transpacific Industries Group, Babcock & Brown Wind Partners, Geodynamics, GRD, Tox Free Solutions, Carnegie Corporation, Dyesol, Hydromet, and Green Invest